A series of 18 related research projects focus upon various experimental aspects of cancer cell biology. Seven of these are specifically directed toward changes in cell surfaces accompanying differentiation, the manner in which cell contacts influence morphogenesis and the disruption of normal surface phenomena associated with tumor cell formation. Four projects concern the control of DNA synthesis, recombination and repair, including the mechanism of DNA polymerase inhibition, the control of thymidine kinase in various developmental stages, and the molecular events related to DNA scission and repair,both in normal meiosis, and in somatic cells following radiation or alkylation. Three projects are directed toward problems of RNA metabolism, including studies on the packaging and transport of RNA from nucleus to cytoplasm, the chemical modification of tRNAs, and the functional nature of ribosomal proteins. Four other studies are directed to problems of cell growth: the nature of the insulin control of protein synthesis in normal and diabetic animals, patterns of regulation in certain hepatic enzymes, particulary glutamine synthetase, the action of humoral factors in liver regeneration, and the relationship between age and secretion in prostate gland. In most of these studies, detailed comparisons will be made between normal and neoplastic cells. Investigations on normal algal (Chlamydomonas), yeast, drosophila, chick, rat, mouse and human cells are outlined; as well as human leukemia, hepatoma, prostatic carcinoma and a variety of experimental animal tumors. A large number of analytic methods, molecular, biochemical, immunological, and morphological, will be employed. The program seeks a fundamental understanding of control mechanisms in normal growth and differentiation, and the manner in which these are altered in oncogenic transformation.